Structural Modal Control and Gust Load Alleviation for a SensorCraft Concept

Vartio, Eric; Shimko, Anthony; Tilmann, Carl P.; Flick, Peter

doi:10.2514/6.2005-1946

Cited by 26 publications

(8 citation statements)

References 7 publications

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“…This current investigation is focused on the effectiveness of gust alleviation by a specially-designed passive twist wingtip (PTWT). This particular PTWT has been studied in previous research for large unmanned air vehicles, including a flying wing aircraft [6,7] and jointed-wing sensor craft [8][9][10][11][12] of very flexible and high aspect ratio wings. The results have shown that the gust load has been significantly reduced by employing such a passive gust load alleviation device with optimized design parameters.…”

Section: Introductionmentioning

confidence: 99%

Gust Alleviation of a Large Aircraft with a Passive Twist Wingtip

2015

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This paper presents an investigation into the gust response and wing structure load alleviation of a 200-seater aircraft by employing a passive twist wingtip (PTWT). The research was divided into three stages. The first stage was the design and analysis of the baseline aircraft, including aerodynamic analysis, structural design using the finite element (FE) method and flutter analysis to meet the design requirements. Dynamic response analysis of the aircraft to discrete (one-cosin) gust was also performed in a range of gust radiances specified in the airworthiness standards. In the second stage, a PTWT of a length of 1.13 m was designed with the key parameters determined based on design constraints and, in particular, the aeroelastic stability and gust response. Subsequent gust response analysis was performed to evaluate the effectiveness of the PTWT for gust alleviation. The results show that the PTWT produced a significant reduction of gust-induced wingtip deflection by 21% and the bending moment at the wing root by 14% in the most critical flight case. In the third stage, effort was made to study the interaction and influence of the PTWT on the symmetric and unsymmetrical manoeuvring of the aircraft when ailerons were in operation. The results show the that PTWT influence with a reduction of the aircraft normal velocity and heave motion by 1.7% and 3%, respectively, is negligible. However, the PTWT influence on the aircraft roll moment with a 20.5% reduction is significant. A locking system is therefore required in such a manoeuvring condition. The investigation has shown that the PTWT is an effective means for gust alleviation and, therefore, has potential for large aircraft application.

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Section: Introductionmentioning

confidence: 99%

Gust Alleviation of a Large Aircraft with a Passive Twist Wingtip

2015

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“…In [5], an adaptive control strategy for damping the first wing bending mode has been extensively tested in a wind tunnel. Another series of wind tunnel studies characterizing the system response and active control characteristics has been carried out on the so-called "SensorCraft", see [6][7][8]. As the wind tunnel tests confirm, the performance of a GLA system largely depends on available measurements and control surfaces.…”

Section: Introductionmentioning

confidence: 99%

Aeroelastic Modeling and Control of an Experimental Flexible Wing

Pusch

Ossmann

Kier

et al. 2019

AIAA Scitech 2019 Forum

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Structural weight reduction and high aspect ratio wings play a key role in improving the performance of modern transport aircraft. This leads to a highly flexible aircraft structure which is sensitive to external disturbances like gusts. To counteract this undesired effect, active control is a promising technology. In this paper, a gust load alleviation controller is designed for a wind tunnel model of a flexible wing with various trailing edge flaps and acceleration sensors. For a sophisticated model-based controller design, a detailed aeroelastic model is derived describing the coupling of structural dynamics and aerodynamics. Additionally, actuator dynamics and structural modes are identified and used to improve model accuracy. Subsequently, the weakly damped first wing bending mode, which causes high structural loads, is isolated via H 2-optimal blending of control inputs and measurement outputs. In this way, a gain-scheduled single-input single-output controller can be designed to control the desired aeroelastic mode. Eventually, the great potential of the proposed control approach is verified by a wind tunnel test including different gust excitations and varying airspeeds.

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“…Increased flexibility leads to wing structure and vehicle rigid body modes being in the same frequency range, allowing the nonlinear structural response to have a greater impact on the system as a whole. Vartio et al [5] documented the results of a wind tunnel test at NASA Langley in the Transonic Dynamics Tunnel of a gust load alleviation system for the Sensorcraft concept. Through the experiment, they demonstrated that a leading edge/outboard trailing edge control scheme may successfully control the first bending and pitch modes for a SensorCraft concept.…”

mentioning

confidence: 99%